In a UMTS (Universal Mobile Telecommunications System) network, long term evolution (LTE) is under study for the purpose of further increasing high speed data rates, providing lower delay and so on (see non-patent literature 1). Also, successor systems of LTE (referred to as, for example, “LTE-advanced” or “LTE enhancement” (hereinafter referred to as “LTE-A”)) are under study for the purpose of achieving further broadbandization and increased speed beyond LTE.
In these LTE and LTE-A, when a mobile station apparatus UE communicates with the network, a cell search process is required to establish synchronization. In the cell search process, the mobile station apparatus UE detects the synchronization signal (SS: Synchronization Signal) that is transmitted from the base station apparatus at regular time intervals, and acquires frequency synchronization, timing synchronization and the cell ID (PCI: Physical Cell ID) of the cell where the mobile station apparatus UE is located (serving cell). Based on the information acquired, the mobile station apparatus UE determines the serving cell. Note that the synchronization signal includes identification information to identify the base station apparatus (for example, a base station ID), so that the mobile station apparatus UE can specify the connecting base station apparatus based on this identification information. Then, by transmitting the RACH (Random Access CHannel) to the specified base station apparatus, the mobile station apparatus UE can report its presence to the cell and secure communication resources.